1. Field of the Invention
The present invention relates to a mouthpiece regulator for a self contained underwater breathing apparatus (scuba), and particularly to such a regulator employing a simplified inlet valve and inhalation pressure responsive structure.
2. Description of the Prior Art
A typical prior art scuba mouthpiece regulator includes (1) a diaphragm sensitive to inhalation/exhalation pressure changes during the breathing cycle, (2) an inlet valve that controls the delivery of breathable gas from the supply tank to the mouthpiece, and (3) a mechanical linkage interconnecting the diaphragm and the inlet valve to cause the valve to open during inhalation. The regulator also includes (4) a separate exhaust port and associated flap closure to exhaust the exhaled gas. This conventional organization is illustrated by the Dalla Valle mouthpiece regulator of U.S. Pat. No. 3,101,732.
While the above described regulator is quite efficient and is widely used, its complexity and relatively large number of components results in increased cost. An object of the present invention is to provide a mouthpiece regulator having significantly fewer components and simplified construction. Resultant benefits include reduced cost and improved reliability, this being of particular importance since life literally depends on proper functioning of the regulator during underwater use.
Another problem associated with prior art mouthpiece (second stage) regulators is that their operation is not independent of the incoming air pressure level. For example, the pressure of the supplied breathable gas may be exerted directly on the valve member that is controlled by the diaphragm linkage. As a result, regulator performance will vary somewhat as changes occur in the breathable gas pressure level supplied from the scuba tank and first stage regulator. Another object of the present invention is to provide a mouthpiece regulator that operates substantially independently of the incoming air pressure level.